Reigniter for automobile heaters



March 5 1940 H. J. DE N. MccoLLuM 2,192,688

REIGNITER FOR AUTOMOBILE HEATERS Filed Nov. 29. 1937 Patented Mar. 5,194() PATENT OFFICE REIGNITER FOR AUTOMOBILE HEATERS l Henryl De N.McCollum, Evanston, lll. Application November 29, 1937, Serial No.177,078

2 Claims.

My invention relates generally to automobile heaters of the internalcombustion type and more particularly to refigniters for use in heatersof this type.

A In heaters of the general type disclosed in my co-pending applicationSerial No. 61,213, iiled January 28, 1936, difllculty was occasionallyexperienced in the operation of the heater due to the fact that thereigniter plug therein failed tofunction under certain conditions ofoperation. For example, the heater might be started in the usual mannerand operate a sufllcient length of time to cause the thermostaticallycontrolled switch to disconnect the electrical igniter from the sourceof current prior to the time that the reigniter plug had been raised toa sumcient temperature to cause reignltion of the combustible mixture inthe combustion chamber. This might occur if the flame in the combustionchamber became extinguished due to an unusual and s sudden decrease inthe intakemaniiold vacuum. l

Under such circumstances, the ame might remain extinguished for a shortperiod until the heater became cooled sufficiently again to cause thethermostatically controlled switch to close the circuit to theelectrical igniter. Such Aoperation had the disadvantage that the heaterwas temporarily ineffective to heat the passenger compartment oi thevehicle and also because of the additional undesirable drain upon theautomobile battery due to the second operation of the electricaligniter.

It is therefore an object oi my present invention to provide an improvedreigniter plug which is effective to maintain combustion in thecombustion chamber after being heated for a relatively short interval oftime.

A further object is to provide an improved reigniter for heaters o! theinternal combustion type in which the shape of the reigniter is suchthat it is rapidly raised to its effective ignition temperature.

Other objects will appear from the following description, referencebeing had to the accompanying drawing, in which:

Fig. l is a fragmentary sectional View of an automobile heaterincorporating the improved reigniter plug of the present invention; and

Fig. 2 is a transverse sectional view taken on the line 2-2 of Fig. l,showing the reigniter plug in elevation. Y

In order that the improved operating characteristics of the reigniterplug may be more readily understood, the description thereof will bepreceded by a brief general 'description of the heater in which it isincorporated.

The heater comprises generally a casting Ill having a combustion chamberI2 formed therein and to which a combustible mixture of liquid fuel(gasoline) and air is supplied through a tube I4 from a carburetingdevice I6, the latter being supplied with liquid fuel through a conduitI8 which is connected to receive fuel from the fuel supply system of theautomobile in which the heater is installed, herein shown as connectedto the oat bowl 20 of the engine carburetor.

Ihe combustible mixture of air and fuel supplied to the combustionchamber I2 is raised to its kindling temperature by an electricaligniter 22 which is generally in the form of a high resistance nichromewire. The products of combustion flow past the reigniter plug 24,hereinafter to be described in detail, and thence through circuitouspassageways formed in a radiator core 26 which is surrounded by a shell21 and heat radiating iln s 28. A Venturi type nozzle 30 is positionedat the end of the circuitous passageway formed in the radiator core 26,Vand is con- A nected by a passageway 32 with a conduit 34 leading to theintake manifold 36 of the engine of the automobile upon which the heateris mounted.

The operation of the heater is controlled by means of a knob 38 securedto a rod 40, which, at its end, has a valve 42 engageable with the mouthof the Venturi type nozzle 30 to cut oi ow of gases through the heater.The control knob 28 also serves as a means for operating ar pairofswitches 44, 46, which respectively control4 the flow of current to amotor 48 which drives a fan 50. and control the flow of current to theelectrical igniter 22. The operation of this switch is such that whenthe control knob :z is puued outwarcny to initiate operation 4 of theheater, the switch 46 will close i'lrst and cause the electrical igniter22 to be supplied with heater current. The electrical igniter havingignited the combustible mixture which is drawn through the carburetingdevice I6 by the intake 45 manifold suction, the heat of combustionraises the temperature of the-radiator core 26 and its associated shell21 to' a' high temperature, the heat being also transmitted to a bimetalthermostatic actuator 52, the lower end of which 50 moves to the left asthe element becomes heated. In this manner, the contacts of the switch46 will first be opened as the heater attains its substantially normaloperating temperature. Shortly thereafter, with a slight increase in thetem- 55 perature of the thermostatic element 52, the latter will closethe contact switch 44, and thus the vfan 50 will beoperated to circulateair from the passenger compartment of the vehicle past the radiator 26,21, 28.

'I'he reigniter plug 24 is made of a ceramic material having arelatively thick central por-4 tion 54 provided with a cylindricalrecess 56 and a plurality of concentrically arranged perfora-.

tions 58 which form passageways for the flow of the products ofcombustion from the combustion chamber I2 to the passageway in theradiator core. Alternate perforations 58Vare intercepted by slots 60extending radially inwardly from the edge of the plug. These slots areprovided to allow for the expansion and contraction of the plug withchanges in temperature.

` Upon initiation of the operation Vof the heater, the hot gases ofcombustion Will surround and impinge against the surface of thereigniter plug, and rapidly heat the latter. The central portion of theplug is in elect thermally insulated from the walls of the combustionchamber so that this portion of the plug will rapidly be raised to thetemperature of incandescence at which it is capable of reigniting thecombustible mixture should the flame become extinguished accidentally.The central portion 54 of the plug provides a suiiicient heat retainingmass around the recess 56 so that the walls of said recess will bemaintained'at an ignition temperature for a considerable length of time.Thus, under adverse conditions of engine operation, when the intakemanifold vacuum uctuatesgreatly, the reignition plug will maintain itsignition temperature during the periods when the intake manifold vacuumis insuicient to maintain the flow of combustible mixture into thecombustion chamber at the rate suilcient to maintain proper combustion.The reigniterplug will, during these periods, cause ignition of such o!the combustible mixture as is drawn into the combustion chamber eventhough th'e rate at which it flows is insuilicient to maintain a steadyame, and unless the period of insuiiicient intake manifold vacuum isexcessively extended, the reigniter will cause reignition and resumptionof steady operation as soon as the intake manifold vacuum is suflicientto cause flow through the heater at a normal rate.

The reigniter plug 24, due to its improved shape, will heat up sorapidly that it will have attained incandescence or at least atemperature surllcient to ignite thev combustible mixture prior to thetime that the thermostatic element 52 opens the electrical ignitercontrol switch 46.`

Thus, during the initial starting period, the combustion will bemaintained in the first instance by the electrical igniter, for a shortperiod by' both the electrical igniter and the reigniter plug, andthereafter, solely by the reigniter plug. As

a result, there is but a very slight possibility that the flame in thecombustion chamber will become extinguished due to extended erraticvariations in the degree of intake manifold vacuum, and the possibilitythat the electrical igniter will be energized more than oncesubstantially eliminated.

Of course, if the operator of the vehicle permits the engine to remainstopped for an extended period, the reigniter plug may cool suiiicientlyto necessitate reenergization of the electrical igniter, but with theimproved reigniter disclosed herein, the possibility that the intakemanifold suction will be reduced for such an extended period duringregular operation of the vehicle is so small as to be negligible.

While I have shown and described a particular form of reigniter, it willbe apparent to those skilled in the art that variations andmodiiications thereof may be made without departing from the essentialfeatures of my invention set forth in the accompanying claims. Itherefore desire, by these claims to include as my invention all such-modifications and variations by which substantially the same resultsare secured in substantially the same way.

I claim:

1. In an automobile heater of the internal combustion type, a combustionchamber, means to supply a combustible mixture to said chamber,electrical means for igniting the mixture in said chamber, meansresponsive to the temperature of the products of combustion owing fromsaid chamber to deenergize said electrical igniter, and a reigniterforming a wall of said combustion chamber and having a central portionof greater thickness than the edge portion thereof, said central portionprojecting into said combustion chamber in the path of flow of theburning gases therethrough and having a relatively deep recess formedtherein, said recess opening into said combustion chamber.

2. In a heating apparatus in which a combustible mixture of fuel and airis supplied to a combustion chamber and the products of combustion aredrawn from the combustion chamber through a heat transfer device by asource of suction which may occasionally fail, a reigniter plug adaptedfor location between the combustion chamber and the heat exchange deviceto reignite the combustible mixture after a short failure of said sourceof suction, said plug being of a ceramic material and having a pluralityof generally cylindrical passageways extending therethrough', saidpassageways being spaced a short distance from the periphery of the plugand at least some of said passageways having communieating slotsextending to the periphery of the plug, said plug having a centralrecess formed in one side thereof.

HENRY J. DE N. yMcCOLLUM.

